Hi Ed, i have not asked the guys at Luxion what method Keyshot is using for 3DM support. On all other flavours of NURBs you get the tessellation option, with 3DM there is no such option, just the import Nurbs Data tick box, so i am wondering if they are using some sort of 'on the fly' tessellation routine with 3DM, I don't know if that's possible or not but would offer an explanation to why it's sluggish when rendering in the live preview screen. It might even be some kind of activity where KS is watching for live-updates from the Rhino plugin. Rhino does have the ability to redefine its meshing density without the user having to re-draw their object.

Martin Spencer-Ford